Self-adaptive equalizer for multilevel data transmission according to correlation encoding

Claim 1

In a self-adaptive equalizer for equalizing baseband signals derived from data signals of a multilevel data transmission system according to correlative encoding, including a transversal filter comprising, in turn, a delay line supplied with said baseband signals, a plurality of variable attenuators connected to the respective taps of said delay line, and an adder for summing up output signals of said variable attenuators to produce transversal filter output signals, wherein the improvement comprises, a first filter for removing said correlative encoding from said transversal filter output signals to produce first filter output signals of positive and negative signs, means responsive to said first filter output signals for producing binary signals representative of the signs of said first filter output signals, a second filter for encoding said binary signals in accordance with said correlative encoding to produce second filter output signals, means for producing difference signals representative of the differences between said transversal fitler output signals and the second filter output signals, and means for adjusting said variable attenuators in compliance with the respective products of each of said difference signals and baseband signals derived from those taps of said delay line to which the relevant variable attenuators are connected.